The present invention relates to improvements for adjustable pallets used in pallet conveyor production line systems for dynamo-electric machine components, and more particularly to apparatus and methods for adjusting the distance between support members of pallets capable of carrying dynamo-electric machine component workpieces of different dimensions.
The apparatus and methods disclosed herein are applicable to pallets having support members such as those shown in U.S. Pat. Nos. 5,060,780, 5,060,781, 5,099,978, 5,115,901, 5,255,778, 5,346,058 and 5,474,166, all assigned to the assignee of the present invention.
Pallet conveyor systems are used in production lines where dynamo-electric machine component workpieces (e.g., armatures or stators for electric motors, generators, alternators, etc.) are to be subjected to a sequence of operations at successive workstations. A workpiece that is to be assembled, machined, or operated on is placed on support members that are mounted on a pallet. The pallet is set upon a moving conveyor that will advance the pallet and the workpiece to a series of workstations that perform a sequence of desired operations to complete the production cycle. A plurality of pallets carrying a like plurality of workpieces are typically used.
The pallets may be frictionally driven by a conveyor. As a workpiece is brought to a workstation, the pallet is stopped and the work station operation is performed. While stopped, the pallet may continue to rest on the moving conveyor in sliding contact, or may be lifted off the moving conveyor. Depending on the desired operation, the workpiece may be worked upon while resting on the support members of the pallet, or it may be removed from the support members, worked upon, and then returned to the support members. At the conclusion of the operation, the pallet is released or placed back on the conveyor to advance to the next workstation. The pallets thus move asynchronously, i.e., pallets upstream of a stopped pallet will advance until they are stopped behind a stopped pallet while the conveyor continues to advance, individually or in sets or groups, and accumulate in order to wait their turn at the workstation.
Pallet conveyor production lines are adapted for performing the same operations on workpieces that belong to the same family of workpieces and require the same machining operations, even though they may differ in certain dimensions. It is known to provide workstations with automatic adjustment devices that can receive workpieces of different dimensions and adjust for the differences in order to properly perform the desired operation. Sometimes support members of pallets in conventional pallet conveyor systems are manually adjusted for the dimensions of particular workpieces for a particular production cycle.
One of the problems associated with adjusting support members of conventional pallets is the redundancy of effort involved in locking and unlocking the support members relative to the pallet. Support members having mechanical connecting links or fasteners are manually loosened in order to move the support members, and then manually re-fastened to secure the support members in a desired location. This re-fastening step is a substantial duplication of the effort expended to unlock the support member. Thus, it would be desirable to eliminate the duplicative manual re-fastening step.
Another problem associated with adjusting support members of conventional pallets is that manual adjustment procedures typically allow for error in the settings used from one pallet to the next. As a result, workpieces are not always properly supported during the production cycle, which may result in differences in the quality of the finished product.